You can find the B5 Systems Sierra K Extension Kit here Fast $9.95 shipping! Orders over $200 ship for free!

The B5 Systems Sierra K Extension Kit is the proprietary mounting system for the B5 Systems Sierra K Buttstock. The Sierra K Kit includes a reduced-length, mil-spec diameter, 7075 aluminum, 5-position receiver extension, a short heavy buffer (3.5 oz), extra power spring, castle nut, and quick disconnect end plate. All parts are made of Mil-Spec materials and finishes. Made in the USA.

Color: Black

Kit includes:

• 5-Position Receiver Extension
• Short Heavy Buffer (3.5 oz)
• Extra Power Spring
• Castle Nut
• QD End Plate